Senators challenged Attorney General Eric H. Holder Jr. on Wednesday over the Obama administration's long-delayed pledge to close the prison at Guantanamo Bay and its plans to try alleged Sept. 11 co-conspirators. But Holder conceded little and emerged from the session mostly unscathed.

Holder has been assailed for months over his handling of terrorism cases. Four weeks ago, he snapped to House Republicans that Osama bin Laden would never appear in a U.S. courtroom and that authorities "will be reading Miranda rights to a corpse." That heightened the expectation that Holder would face a grilling from the Senate Judiciary Committee on Wednesday.

But the attorney general held his ground or side-stepped most hostile questions from Republicans, and he managed in a controlled, cautious appearance to do little new damage to his political standing on Capitol Hill or with the White House, aides said.

Holder used his 3 1/2 -hour testimony -- his first before the committee since the collapse of his plan to try Khalid Sheik Mohammed and four other alleged Sept. 11 plotters in federal court in New York City -- to dig himself out of more recent controversies.

He said that the United States still hopes to capture and interrogate bin Laden, but added that it was "highly unlikely" that the al-Qaeda leader would be taken alive, given what is known about his instructions to his security forces.

Holder also defended the decision to bring civilian criminal charges against Umar Farouk Abdulmutallab, accused of attempting to bomb an airliner on Christmas. That decision has been "shown to be the right one," he said, citing information provided by the Nigerian since he began cooperating with the federal government after his arrest.

Senior administration officials have privately expressed dismay about Holder's job performance, saying he has displayed a tin ear in his decision-making and his public remarks. That has prompted predictions that he might not last much longer, but Holder has shown no signs of getting ready to leave, and he remains a close friend of President Obama's, advisers said. If anything, his careful statements Wednesday seemed to suggest that he is adapting to the White House's desire that he make less news.

Holder said it would be a "number of weeks" before the White House-led review of his decision to try Sept. 11 suspects is concluded. He also insisted that officials have not ruled out New York as a site for the trials.

"New York is not off the table," Holder said. "The Southern District of New York, for instance, is a much larger place than simply Manhattan."

The remark prompted exasperation even from Democrats.

"We know the administration is not going to hold the trial in New York. They should just say it already," said Sen. Charles E. Schumer (D-N.Y.).

Sen. Benjamin L. Cardin (D-Md.) expressed impatience with the administration's indecision on how it would indefinitely detain subjects whom it cannot prosecute because of the nature of the evidence against them, but who are deemed too dangerous to release.

"I've heard you say frequently 'as soon as possible,' but it's getting late," Cardin said. "This is an issue that is difficult for us to defend, when we . . . don't have a policy to defend."

Republicans were mostly critical of Holder, accusing him of undoing Bush administration policies and weakening the U.S. response to terrorism.

Sen. Lindsey O. Graham (R-S.C.) said he supports Obama's push to "fashion detention policy that allows us to be at war within our values," and he agreed with military commanders that closing the prison at Guantanamo Bay, Cuba, is important to bolstering support from allies abroad. But without a political consensus on where to move those detainees or funding for a proposed facility in Illinois, he said, "we're basically a nation without a viable jail."

Sen Jeff Sessions (Ala.), the ranking Republican on the panel, bluntly said Holder is endangering Americans by not backing off a "presumption" to try terrorism suspects in civilian courts, instead of before military commissions. And he criticized Holder for refusing to admit that he erred last fall in saying the government would make its strongest legal case in New York -- a decision Holder called "a close call" on Wednesday.

"Your actions have shaken my confidence in your leadership at the Department of Justice," Sessions said. "The course you've chosen on national security is steering us into a head-on collision with reality. . . . Pretending that terrorists can safely be treated as common criminals will not make it so."

Holder responded that, at the same time he moved to send the five Sept. 11 defendants to New York, he announced that the Pentagon would conduct military commissions for five other detainees in Cuba. And Senate Democrats argued that the Bush and Obama administrations have used both criminal prosecutions and military tribunals in what Holder called a "flexible . . . pragmatic . . . and aggressive" response.

Americans' best interests are served by "maximum flexibility" in the treatment of detainees, said Sen. Dianne Feinstein (D-Calif.), adding that the Bush administration secured 200 terrorism convictions in civilian courts. Military commissions -- whose procedures faced legal obstacles for years -- have led to three convictions, she said.